I guess it's my turn to say it in a thread:

Shattered pixel dungeon

Best classic roguelike on mobile IMO

I was going to also suggest Downwell but it doesn't seem to be available any more

I am quite partial to Puzzles

https://play.google.com/store/apps/details?id=name.boyle.chris.sgtpuzzles

https://f-droid.org/packages/name.boyle.chris.sgtpuzzles

If you enjoy pinball, this one is decent: https://f-droid.org/packages/com.dozingcatsoftware.bouncy

I would highly recommend Monument Valley (1,2 and 3 is coming soon) as far as puzzle goes, for a quick arcade fix, I like Breakout 71 (with rogue-lite elements) and all games by Arnold Rauers (Card Crawl being my favorite, but by a small margin).

Here's a quick selection from the top of my head, if you want I can go throw my app history for a few more :)

Tessel is a beautiful tile puzzle game

F-Droid

• Tessel
• Ricochlime
• Shattered Pixel Dungeon

Deep rock galactic survivors is on mobile now and it works in both portrait and landscape mode

I haven't played it in a million years but I remember Cut The Rope being really fun.

magic survival

I love puzzle games, either ones with an overaching story or standalone puzzles. I love the professor layton series Googke Play Store. I believe you should also check out Monument Valley Google Play link. If you're looking for a FOSS option, there's Simon Tatham's puzzle collection F-Droid Link

It’s an older game, but Downwell is fun. Just a little action/arcade game where you fall down a well and try to get combos by not touching the ground by bouncing off of enemies.

https://play.google.com/store/apps/details?id=com.devolver.downwell_rerelease

Here are some FOSS games on Android that can be played on a portrait orientation.

Mental Math

Tessel - A tiling game

Flang - it's like chess, but not chess.

2048

BlastOff - endless runner

Chip Defense - it is a tower defence type of game, and is one of my favourites. You should try it.

Slay the spire!

Sudoku by SecUSo

Slice & Dice is a dice building rogue like, didn't originally have portrait mode, but they added it in at some point, I love the hell out of it

Downwell is one of the best mobile games of all-time

https://play.google.com/store/apps/details?id=com.devolver.downwell_rerelease&hl=en_US

I hope you like rogue-like deckbuilders... I think all of these are either paid or you can pay to remove ads.

• Night of the full moon
• Pawnbarian
• Card crawl
• Card crawl adventure
• Card thief
• Maze machina
• Lost 4 swords
• Enyo
• Void tyrant
• Solitairica
• Wordlike
• Cards of Terra
• LOK

Currently playing Block Blast as my time killer and loving it.

Square Valley

A Way Home

Dicey Elementalist

Perfect Grind

The Way Home

The original Shapez is vertical. I don't love how it plays on mobile in terms of controls but it works

I don't play many Android games, and enjoy even fewer, but Hoplite is great. It's pretty simple to play but still requires some thinking, which is what I want out of a mobile game.

https://play.google.com/store/apps/details?id=air.com.midjiwan.polytopia

I play this one more than I should

Downwell

Here is a paid gem:

Idle of Arrows (Play Store)

Gonna go with the wildcard here and suggest Walkscape. It's still in beta, so access requires a one-time patron sub ($4.50, then cancel) or a free written application through their portal (may take like a week to approve)

It's a classic runescape-style RPG where all actions cost "steps" walking. It's designed to keep screen time to a minimum and walking time to a maximum.

Character management is generally pretty passive and 1-handed. Definitely much more casual by nature, but encourages much more active participation.

Once Upon a Galaxy has been my default game since I first played it.

It's an asynchronous alternating activation autobattler (like Arcane Rush, or Storybook Brawl/Hearthstone Battlegrounds but you play against ghosts). Games take about 10-15 minutes.

It's largely public domain fantasy themed, but has been expanding into the "legally distinct" cultural references as they add content, basically every captain/unit/treasure is a reference.

The shop mechanic is simplified, there's no currency, you just get a set of choices, and can pick 1. You get two shops per round by default, lots of ways to get extra.

Asynchronous play means that you face challenging opponents that naturally evolve with the meta game but you can also take time to make thoughtful decisions.

The draft pool for the shop has a large base pool that you add to by selecting a custom sebset from a second large pool as your captain's deck. The progression is through unlocking cards for each captain's secondary pool, and unlocking new captains. You can naturally earn all cards through play, most captains are free, new captains are paywalled for a limited time.

Monetization is through 3 paths: cosmetics, acceleration of card unlocks, access to paywalled captains. I haven't found it to be particularly exploitative or negative feeling.

My only gripe is minor, that it doesn't have mid-run save/resume, but that is on their road map.

There is essentially no story, if that matters to you.

If it's not obvious, I'm really enthusiastic about this game. I'm not affiliated/sponsored in any way. Happy to answer any questions.

Rogue Adventure is great. I recently switched to iOS but I miss playing this game.

Link

Dawncaster is a great deck builder that's vertical if you are into those!

Surprisingly, mindustry hasn't been mentioned yet! Great quality, well thought out, addictive combination of tower defence, RTS and factory building.

I would say Umamusume but don't get into it if you don't really have much time.

Dungeon Tracer is a pretty decent remake of one of my favorites from back in the day, Dungeon Raid

Here is one that is quality and engaging if you like a good story:

80 Days

Pilgrims. Its a puzzle game, no dialogues but great story. Not FOSS.

https://amanita-design.net/games/pilgrims.html

It's a paid game, though. I got it for free from Epic Games.

You can play it on any device. On phones, it is played in portrait orientation.

https://play.google.com/store/apps/details?id=vo.threes.exclaim

https://play.google.com/store/apps/details?id=com.eightyeightgames.ymbab