I know for a fact that some features of HLAE that work in CS:GO do not work in TF2 (for example, multi-pass). So even though the reshade guys wrote "Source games", I have a strong feeling they didn't test it on TF2 and that it does not work in this game.

https://www.youtube.com/watch?v=QB_2qn1dj58

https://imgur.com/a/KpOQj the red lines are intersections with the x and y axis - both variables on their own have a local maximum at that point. But the blue guide lines lines have a minimum. obj - https://mega.nz/#!OlgjTDhQ!6mm3oZqd0k_uqgj9Aa-tLJMG-rtGc6Ar4QbRaffFGHU

It can be a saddle, oriented diagonally like this - https://imgur.com/a/A7sjD

deadbolt & paragon

Check Dustforce if you want to try a very good 2d platformer. Also I second Bastion, the soundtrack alone is amazing.

idk if roguelikes fit your criteria, of those I can recommend Binding of Isaac, Nuclear Throne, Spelunky HD, Crypt of the NecroDancer

ds_mark is a console command, you can bind it to a key just like any other command by typing
bind <key> "ds_mark"
in the console. For example
bind h "ds_mark"

Personally I have it set on the numpad keys, those look like kp_<name>, for example kp_end or kp_home

It can be set-up through the advanced options menu. You can set prefix and autodelete, etc. Type "find ds_" in console to see the list of the commands. ds_mark makes a bookmark

The TF2 edit community is pretty small. Off the top of my head, apart from me there are

SynciNG
Uil
weatherspoon
jay
jacoldoer
klm

Inactive
mahninjA
hakka
FreezeR
Pixelrelic
cube
w3stracer
deli

Funky Visions people (all inactive)
NaF
0t1z
Cla
dellort
ikpure
grid (unlisted his vids, here's another one)

TF2 RJWEEKLY people (not really over-edit but i felt like i had to mention them)

https://clips.twitch.tv/GrossVictoriousShield4Head

https://youtu.be/78RzwMIHn5o

its Jake Chudnow - Short Stories

https://www.youtube.com/watch?v=ESA7yu1x4UM

cl_showpos 0; alias cl_showpos ""

generally this can prevent the player's cfg from executing in pov demos (flickering viewmodels and net_graph on/off, etc)

edit: what are the odds haha

https://www.youtube.com/watch?v=cd4-UnU8lWY