First thing, that really caught my attention was that the plot goes really quickly. You don't really realize what was today and what yesterday and it gets mixed up. Also, in my opinion she is talking with guys like she left for a summer or a few months and get back, not a few years. The beginning could me described a little more and they should be a little more awkward around each other (I think).
If he was so angry at her, well, I do not understand his behaviour.
These are my major objections. You may think I'm brutal, but I am not, exactly. The plot is interesting and the game has more potential. I enjoyed all of the routes, and I greatly enjoyed the game.
Another little thing is, you could work a little bit more on sprites, it's visible not the whole background was erased, and if you know your way around in graphic programs, you can easily do it. If you do not, just google erasing backgrounds. There are many tutorials and this would improve the game experience greatly.
If I were to rate the game, I'd gave it 3,5/5. What I enjoyed the most was the lovely personality of main character (thank God it stays the same no matter what route you pursue! Good work on that), the interesting information about your (I assume) language, I actually feel like I've learnt something! Tee-hee! Also, I love Arvin's character. I just wish there were more details about him, like... Casey could explore his actual life a little bit more. I'd love that.
Well, that's it! You have done a great job, and I wish you more successes!