Thanks for taking the time to give it a play! Good to hear that you liked the sprites and general feel.
Any wall jumping was not intentional, but I know the likely cause. I messed something up with the tile-based collision code, and couldn't quite get it hammered out in time. The original issue was that, upon landing, sometimes it would register a "wall" hit on open floor (probably due to the actor technically being partially in the floor on a landing) and cause an abrupt stop. Since I didn't have the time to figure it out and rewrite that, I switched the order of the check directions (vertical first instead of horizontal), which fixed the landing issue, but probably caused the possibility of registering a "floor" hit while against a wall. Thanks for letting me know that such an issue still exists!
And yes! I do have plans to work on more GBA entries in the future. I've tried before with Butano, but just couldn't quite get things to work how I wanted. But now I have a lot more knowledge and a good foundation to work off of to build a better engine next time around (and hopefully get the game embedded in the page in the future).