Thanks so much for playing. If I could go back I think at the start of the second wave I would have sent out a lone red zookeeper and not started the wave again until the player took him out so hopefully they understood you have to bam the barrel into his jump. That's what's so great about feedback in game jams. You learn a ton. Thanks for sharing.
The yellow bananas increased your barrel armor, so one barrel could eventually take out three zookeepers before bursting. The sprite for the barrel even changes, but I don't think it's nearly noticeable enough. The green bananas reduce your recovery so you can press the action buttons quicker. Again, should communicate more clearly to the player. All great feedback and things to think through if I want to update or for future jams!