Nice gbsenpai entry.
If you had issues with enemies you should get in contact with gbsenpai's author or even better, post an issue on its repo.
Viewing post in Dungeon Advance jam comments
Upon looking into the issue further, it turned out that the problem was with GB Studio and not gbsenpai. I thought actors in platforming areas would be affected by gravity like the player, but that is not the case. The larger screen that putting the game on GBA provided just made the issue more obvious, as enemies would walk on air sooner.