Almost every achievement can be obtained with no tactics or easy tactics, but those achievements need some tactics. Sure, you can obtain them with playing endless mode endlessly, but it's not wise.

1. Challenge - Star
Must have - Desert Trek
Should have - Forgotten Dream, Removing Curse Encounters, Inquisitor's Raiment (Counter First Curses), Counter curse Items
1.1 How
You always get the 4 curses during this challenge,
The first one, 2 foods whenever you face new encounter
The second, Damage card whenever you face new encounter
The third, is whenever you face new encounter you get curse.
It's simple, go floor 3 and get the third curse and just move.
Since having lots of curses makes your battle extremely hard, you should finish it with Desert trek.
If you didn't remove your first and second curse, it's really hard to keep you alive.
So remove them even though you need 2 more curses to get this achievement.
Also if you face Desert trek and Forgotten Dream both before floor 3, just restart.

1. Challenge - Judgement
1.1 How
It's Simple
1. Prepare for Max HP / Blessing Encounters and Items (Don't try to get them both, just do 2 run for each achievement)
2. Face every encounter and kill everything to get Max HP or Blessing, don't recommend to follow goblin.

1.2 Why not Endless mode?
It's not hard to get those achievements in Endless mode as Infernal but it takes really long time and tedious. More than 5 hours I guess, 20+ floor

1. Endless mode
1.1 How
You don't have to discard 30 blessings in 1 Game, so You should play about 3 runs easily.
Just play normal and throw blessings when you play for another achievement.
And Count it how many you drop blessings with your Leaderboard.
Normally, you can about 25 blessings when you try to get 25,000 scores.
So throw them all when you can meet the conditions.
If you need to play more, just ALT + F4 for saving games before finishing encounter.

1. Endless mode
Tactics: Get 5 curses when you face the encounter.
Why?
It's really harder to play game having some curses but there are few ways to remove curses in endless mode.
So finish it ASAP.
There are some lethal curses which make your game really hard but you still need to get 5 curses per 1 encounter.

1.1 Tips
The Most powerful removing curse encounter is The Underneath.
You can delete every curse in this encounter but you have to discard every blessing too.
You might feel losing blessings is too bad for your run especially permanent one.
But if you got a blessing as reward, you can get it in another encounters if you discarded them.

The Most important item is Kings crown.
It can protect you from getting 1 curse.
So get it early and use it when you get the most lethal curse.

Spiked Boneguard will protect you getting 1 curse per 1 Spiked Boneguard and you can't stop its activating.
So when you protect 1 curse with this item, sell it and try to get new one.
Also when you meet keeper of sorrows with this item, choose the most lethal curse first.

Veles is the best companion because he has map revealing when you try to get this one.

It is recommended to get this achievement while not playing game to get 25,000 scores.
You can finish it before 25,000 scores but getting curses for this achievement makes game really hard.

Those achievements are not so hard but need some times.
So Good Luck!