I put the stats for lvl 1, lvl 10 and add +x stats until level max reached (supposing the tower is lvl 20)
As for the abilities, i'm putting the stats for the lvl 1 and lvl 20 (less if mentionned (like the ultimate))

Name : Hell Tower

Shape : square with a circle in its center emitting red light

IG description : shoots a beam of light doing damage that increases over time. Max 2 ennemies

Stats for lvl 1 : / Lvl 10
Damage : 17-340 / 100-2000 (+7-30/ EXP lvl above 20)
Rotate speed : None (the tower will imediately target and damage the ennemy)
Attack speed : 1.5/sec / 4/sec (+0.08/sec / EXP lvl above 20)
Range : 4.60 / 10
Minimal damage increase by 10% every second of non stopped shot on the same ennemy (is not affected by power) (can be increased with research) (note : the research stat is below)
Price : 360

Minimal damage increase research : add 1% for each upgrade (level max is 11)

Ability : ​
Hell Burns : Deal 0.3% of ennemy max HP every shot (except on boss) and deal 50% of the minimal Tower damage (lvl 1)
​Deal 1.2% of ennemy max HP every shot (except on boss) and deal 95% of the minimal Tower damage (lvl 20)

Multi-Targets : Can targets 1 more ennemy (this target ignore the targets priority) (lvl 1)
Can targets 11 more ennemy (those targets ignore the targets priority) (lvl 20)
(Note : It give +1 more target every 2 upgrades and give +1 more target when upgrading to lvl 20)

Hyperburner : increase the maximum damage by 50% but reduce the "minimal damage increase" by 8% and inflict vulnerability +5% for 1 sec (lvl 1)
Increase the maximum damage by 250% but reduce the "minimal damage increase" by 15% and inflict vulnerability +10% for 1.5 sec (lvl 20)

Lvl 10 (EXP) ability :
Hades Power : The ennemies attacked have now an aura, dealing 2% of their max HP to the ennemies around in a 0.3 tile radius. Ennemies killed by the aura explode, dealing 1000% of the turret damage in a 1 tile radius (lvl 1)
The ennemies attacked have now an aura, dealing 5% of their max HP to the ennemies around in a 0.5 tile radius. Ennemies killed by the aura explode, dealing 2000% of the turret damage in a 1 tile radius (lvl 20)

Lvl 20 (EXP) ability :
Powerful : Power x (i forgot the maximum value)

Ultimate : The turret deal 300% of the minimum and maximum damage (1200% if Multi-Targets have been choosed) but cannot target more than 1 ennemy. If an ennemy is killed by this tower, this tower gain 1% of minimum and maximum damage (4% if Multi-Targets have been choosed), stackable 50 times and last 45 secondes. (lvl 1)
The turret deal 500% of the minimum and maximum damage (2000% if Multi-Targets have been choosed) but cannot target more than 1 ennemy. If an ennemy is killed by this tower, this tower gain 2.5% of minimum and maximum damage (10% if Multi-Targets have been choosed), stackable 75 times and last 60 secondes. (lvl 20)

Effectiveness against enemies (in %)
Regular - 100
Fast - 25
Strong : 50
Armored : 150
Heli : 50
Jet : 100
Light : 150
Toxic : 75
Healer : 0
Icy : 200
Fighter : 50
Boss : 100

Time for some explanations :
Minimum damage is the first number of the damage, maximum is the second number of the damage (i.e 17-340 ; 17 is minimum, 340 is maximum).

Increasing damage is the amount of minimum damage inflicted (i.e 17 minimum damage become 18.7 damage due to the damage increasing/sec and multiply that number by 1.1 After each second).

This Tower reach his Maximum damage after (research lvl 0) :
0000043:0000032 sec

This Tower reach his Maximum damage after (research lvl 11) :
0000021:0000017 sec