There are 10 achievements in this game, 1 for starting the game and 9 for completing each of the 9 levels. ~1-1.5 hours to complete the game.

There is free DLC for unlocking a H-scene for each level in the main menu under "Memory".

Scene 1-1 will give you a full tutorial on the game. I recommend playing through Scenes 1-1, 1-2, and 1-3, breaking all objects and saving your supplies. For all levels on scenes 2 and 3, I recommend using your supplies to purchase the Hunting Rifle EXII and 2x Hunting Rifle Ammo 24. I found this weapon to be the quickest at clearing and 48 ammo is usually enough for each level. Keep an MP5 or other weapon to finish off enemies with low HP instead of using another hunter rifle shot.











You need to activate a certain amount of runes on each level, the number per level is indicated at the top of the screen when you load in. Press M to get trackers to the runes on each map. There are usually more runes than required on each level. Once enough runes have been activated, move to the teleporter indicated by the green diamond on your screen to complete the level and get the achievement for that level.