This guide was based and made from coofer's run. Some things were tweaked to make the run less confusing or just easier in general. There is a lot of text however so be prepared to read. Act 1 has no thorough guide on how to complete it but the two words listed will probably give you enough information. Its route can be changed with the other route but this one is the easiest. There are also item counts on some of the lines in the act 3 route. Those are to keep your inventory ready for any future items that you must get. Anyways, here's the guide:

act 1: magnet gun route

act 2: flip 3 orange levers [also grab wrench]

use valve on 5 red pipes locations: above ladder in front of house through bedroom door inside house through side window above basement exit

act 3: flip ladder lever [2 items] go through moon door and grab green gramophone [2 --> 1 item] go down window on right side [left side of neighbor's house] grab cake #1 and turn valve 3 times; also use and leave green gramophone and flip levers to the right [2 --> 1 item] go on tracks and get mannequin #1 [window to market room; beside train control room] - [2 items] turn on train and restart go through sun door and grab cake #2; also grab guitar and finish keycard puzzle [4 --> 3 items] grab globe from below and grab umbrella; drop mannequin and both cakes down hole and complete market [4 --> 2 items] grab magnet and turn painting [2 items] get crowbar and cool down in upstairs bathroom; restart [3 items] throw crowbar in front of neighbor's house, freeze globe, grab mannequin #2 [code: 2369], and go up ladder; grab red gramophone [4 --> 3 items] shrink plants in station 2 and grab mannequin #3 [4 items] go in train and setup roof jump; use umbrella for safety drop both mannequins near ladder, grab and use wrench, and shrink roof plants [4 --> 2 items] leave red gramophone, grab mannequin #4, float down to grab cake #3, and leave umbrella [2 items] pick up both mannequins and restart [4 items] place mannequins and cakes around table and get gun [4 --> 1 item] go up house ladder [restart if neighbor is there], go up roof ladder, drop gun, grab green key, and restart [0 -->1 item] go to red key room, pull down lever to reveal gun, shoot items and flip lever, and restart [2 items] grab red key and go to darkness [2 --> 1 item] go down to fear school and use green key [0 items] grab keycard/crowbar, use them on door, and finish act 3 [2 --> 0 items]

finale: grab ball and throw it at switch activate train button, follow tracks, get candle, and light firework go inside the toaster and go up wooden platform grab umbrella from on top of light switch quickly and float down to baseballs push baseball in shooter/machine and light up crossbow go back in toaster and go to blue platforms float down to blue platform near house and enter finish shadow boss and run is over