You got to level 5! Well done!
Exactly like you said it should get harder as you go, with the money you have collected you could have bought cards in the shop. Those cards are now in the deck builder where you can select which cards you wanna have in your deck for your next playthrough in which you could go further!
Pretty buggy for 1 bug? That is pretty harsh - Yes that is a bug turns gained/lost are in fact only visuall and you only have 60 turns to complete the level.
I agree the animations could be faster but to avoid further buggs whe have decided to leave delays a little longer so the game processes do not overlap.