I assume you're on Windows, so I would recommend to use Artmoney for that: http://www.artmoney.ru/e_download.htm not a trainner but rather a generic RAM's value altering (Cheat) program

HP are in in 1-byte integer which represent the number of red triangle. Freeze this number so only the deadly fall that would able to kill Kyle.

Items occupies 2 bytes each, even number of item types are less than 255.
Usable Item digit:
4 = Heal Potion
5 = Hover Bomb
6 = Levitator
7 = Bridge Key
8 = Remote Wasp Bomb
10 = Fire Bomb

EDIT: this thread need to be moved, as its mention using DOSBox and that mean its on wrong subforum.

Many thanks for the program. Would you kindly elaborate a bit more? I have downloaded the program, but I am not sure where I need to input the values.

Thanks!

run both blackthrone (dosbox) and the artmoney
start the game
switch to artmoney, on select process, choose dosbox.

now we gonna see change the HP as its easier, count number of of HP (the red triangle), for example the current HP was 6,
so switch to artmoney, click Search,
select search as exact value,
type 6 on Value,
select Type as Integer
click OK
There should be some addresses found, you need to filter them more.

So, how to filter them?
switch back to the game, and let kyle injured so he lost some of his HP, for example now HP is 5
switch to artmoney, click filter
type 5 on Value
click OK
Now number of the address listed should be decreased, but if its still too much.
Therefore switch back to the game, and let kyle injured again, and repeat the filtering process once again

Eventually, you'll see only 1 adress listed.
Double click it, and it will shown in table area,
Click the newly added entry, you change the description, or change the value, or freeze said value.

Artomey site also provide tutorial how to do that: http://www.artmoney.ru/manual/english/exact.htm

While generic RAM value altering utilities are very nice in general, Blackthorne does happen to have a number of existing trainers.

I've attached two of them to this post, in a ZIP file. They need to be run from the game directory. BTTRN.COM is a simple one - it only allows you to select unlimited health. BTHRN-T.EXE has more options - you invoke it in game (using Numpad *) and can modify the number of hitpoints as well as the inventory.