Here is the full list of all 14 Obscure Realm achievements.
Finished the First Level
Finished the Second Level
Finished Third Level
Finished Fourth Level
Finished Fifth Level
Finished the Sixth Level
Gain 10000 Score
Kill 1 Spider
Kill 1 Shadow
Kill 1 Slugger V1
Kill 1 Slugger V2
Talk to charlie for the first time
Find Charlie in Level 4
Found the old man