I played through the game on both easy and normal and a bit of hard but I gave up on stage 2 on hard mode because it was pretty brutal.
I'll start by getting the elephant in the room out of the way: The frame rate is sub-par. It's not major but just to have the game run at a decent framerate I had to set the quality to the lowest setting. Doesn't sound good but thankfully this game is really short with only 3 levels.
The plot however is kind of confusing. It's unclear who you are supposed to be playing as and the only way the game implies that you are playing a sonic horror game is having Sonic be the antagonist, The entirety of stage 2 and the metal sonics comming to get you in stage 3. Other than that there is 0 implication. This isn't nessicarily a bad thing but with a game this short it sticks out. I however claim Cream's adventure by Tailsguy worse of short length because at least with this game the run-time is at least 10-15 minutes long.
Stage 1:
A practically easy level to start things out on. And in all fairness it is just that. All you have to do is find all the monitors that have codes to type, get rid of pop-ups, type in the codes and enter the schoolhouse. Easy but kind of TOO easy. I beat it on my 1st try on all 3 difficulties which is fine with Easy because there are lights on making seeing Sonic easier but with hard there is no excuse. I think Sonic moves faster on hard but I wasn't sure.
Stage 2:
This is where the education theme came from huh? Anyway this stage is a obvious Sonic's schoolhouse level and you just have to answer questions with Sonic chasing you down. Sounds like a simple Baldi clone and in all fairness it is one even if normal removes the HUD. The REAL problems come into hard mode. I don't know if it is a feature or a bug but for some reason I died while transitioning into stage 2 on hard mode and another Sonic just spawned so I had to put up with 2 of them throughout the stage. What's worse is that being brought to detention is a death sentence if Sonic is in the hippo's path. In Baldi's Basics being brought to detention just warped you there so if Baldi is right behind you he has to head there himself. In THIS game however you get taken there which is more realistic but if any of the Sonics are in the way you are pretty much dead because you have no invincibility frames. I couldn't even answer a question in the reading subject on Hard.
Stage 3:
Hey look! A FNAF clone! This one however is the easiest to get the feel for. Just survive until the timer runs out, Don't let the security become hacked and if a Metal sonic is approaching from one of the doors just close it. I think the harder difficulties just increase the timer because I never got to this stage on Hard mode. Though I do kinda like how you can actually leave the office and if you do that the doors close leaving you to fend for yourself in the fast food joint which will likley end in your death. Nice touch but how do you explain the Metal sonics going through doors if you close them when they make it into your office?
So yeah. I found this a average game. Namely because of how the other characters besides the hippo barely relate to Sonic the hedgehog. Had the others actually feel like they were from Sonic and it would have ben a okay game.